Product Manual - Disc Drive SCSI-2/SCSI-3 Interface (Vol. 2; Ver. 2), Rev. E
71
_____________________________________________________________________________________
4.9.2
Incorrect initiator connection
An incorrect initiator connection occurs on a reconnection if:
(1) an initiator attempts to reconnect to an I/O process, and
(2) a soft reset condition has not occurred, and
(3) the initiator does not send an ABORT, ABORT TAG, BUS DEVICE RESET, CLEAR QUEUE, CONTINUE
I/O PROCESS, or TERMINATE I/O PROCESS message during the same MESSAGE OUT phase as the
IDENTIFY message.
An incorrect initiator connection also occurs on an initial connection when an initiator:
(1) attempts to establish an I_T_L_Q nexus when an I_T_L nexus already exists from a previous connec-
tion, or
(2) attempts to establish an I_T_L nexus when an I_T_L_Q nexus already exists unless there is a contingent
allegiance or extended contingent allegiance condition present for the logical unit or target routine.
A target that detects an incorrect initiator connection shall abort all I/O processes for the initiator on the logical
unit or target routine and shall return CHECK CONDITION status. The sense key shall be set to ABORTED
COMMAND and the additional sense code shall be set to OVERLAPPED COMMANDS ATTEMPTED.
An incorrect initiator connection may be indicative of a serious error and, if not detected, could result in an
I/O process operating with a wrong set of pointers. This is considered a catastrophic failure on the part of the
initiator. Therefore, host-specific error recovery procedures may be required to guarantee the data integrity
on the medium. The target may return additional sense data to aid in this error recovery procedure. Also,
some targets may not detect an incorrect initiator connection until after the command descriptor block has
been received.
4.9.3
Selection of an Invalid Logical unit
The target’s response to selection of a logical unit that is not valid is as follows.
In response to an INQUIRY command the target shall return the INQUIRY data with the peripheral qualifier
set to the value required in Table 5.1.1-8. In response to any other command except REQUEST SENSE the
target shall terminate the command with CHECK CONDITION status. In response to a REQUEST SENSE
command the target shall return sense data. The sense key shall be set to ILLEGAL REQUEST and the
additional sense code shall be set to LOGICAL UNIT NOT SUPPORTED.
